136 SPONTANEOUS GENERATION. 



abundance as to literally jostle each other for room in every drop of water 

 extracted for examination ? The heterogenists, including notably MM. 

 Pouchet and Pennetier, have asserted that the highest Ciliate types present 

 in hay-infusions, such as Colpoda and Vorticella, are generated de novo out 

 of the filmy pellicle, or so-called " proligerous membrane," that in the course 

 of a few days makes its appearance upon the surface of the liquid. This 

 proligerous membrane, again, is further represented to be formed from the 

 accumulated dead and floating bodies of Monads, Bacteria, and Vibrios, 

 that first appeared in the infusion, and to constitute a kind of primordial 

 stroma or pseud-ovary, out of the granular constituents of which, through 

 coalescence at various points of the component particles, true eggs are 

 developed, giving birth to such Ciliata as sooner or later appear upon 

 the scene. The Monads themselves are treated as primary motile mole- 

 cules, occupying a place midway between the organic and inorganic, and 

 possessing motile properties most nearly corresponding with the molecular 

 or Brownian motions of minute inorganic particles. The spontaneous 

 derivation of these Monads from the dead and disintegrated particles of 

 the macerated hay is regarded as too obvious to need discussion. It has 

 been positively ascertained by the author, however, that these minute 

 beings are derived from spores which literally encrust with their countless 

 numbers the stalks and blades of the vegetable matter ; these again being 

 the product of pre-existing monad forms, whose active life was passed in 

 close association with the green and growing hay under the circumstances 

 hereafter narrated. 



In order to arrive at a comprehensive insight into the life-phenomena 

 and progressive developmental manifestations of the special group of infu- 

 sorial animalcules now under consideration, hay from different localities 

 was placed in maceration and examined continuously, from its first contact 

 with the fluid medium, for periods varying in duration from a few days only 

 to several weeks. The water added to the hay was of the purest possible 

 description, and was frequently boiled for some time to prevent the intro- 

 duction of extraneous germs. In all instances, the results obtained were 

 broadly and fundamentally the same, and differed only with respect to 

 the specific types found living together in the separate infusions. Even 

 here, however, the general dominance of two or more special forms was 

 notably apparent. Commencing with the first wetting and simultaneous 

 examination of any given sample, spores of different sizes were found 

 congregated in countless numbers, and in various orders of distribution, 

 throughout the surfaces of the vegetable tissues. The majority of these 

 spores were excessively minute, spherical, of the average diameter of the 

 I-20,000th part of an English inch, and required necessarily the employment 

 of the highest powers of the compound microscope for the correct registra- 

 tion of their characteristic form and size. Sometimes these spores were to 

 be observed collected in definite spherical heaps, but more often they were 

 scattered in irregular-shaped patches, such patches being often again more 



